Method for Measuring Short Circuit, Open Circuit, and Leakage of a Circuit with a Multimeter
A multimeter is often used. This section will explain how to test for short circuit, open circuit, and leakage problems in a circuit, and how to measure short circuit and open circuit with a multimeter after a circuit trip occurs.
1. Short circuit measurement with a multimeter
Operation method:
Insert the black lead of the multimeter into the "com" hole and the red lead into the "V Ω" hole, and adjust the knob to the beep position.
Disconnect the power supply of the tested circuit and measure the two wires of the circuit with two probes. If the multimeter shows a resistance of 0 and there is a beep, it indicates a short circuit in the circuit.
Alternatively, use Ohm 1k or 10k to disconnect the other end of the line and test both wires with two probes. If the multimeter shows a resistance of 0, it indicates a short circuit in the line.
2. Multimeter test for open circuit
Operation method:
When testing the continuity of the circuit, it is necessary to disconnect the power supply before testing.
Turn the knob switch to the beep position, and test that both ends of the circuit are in contact with the metal needles of the probe. If there is a certain resistance and a beep sound, it indicates that the circuit is conductive; If the resistance is infinite, displayed as 1, and there is no beep, then the line is disconnected.
Alternatively, select 10k gear with a multimeter and short circuit the other end of the line. Use the multimeter's probe to test both lines. If the multimeter shows a resistance of 1, it indicates an open circuit; Displayed as 0, it is possible that the circuit is conducting.
3. Measuring Leakage with a Multimeter
There is leakage in the circuit, and it is generally not recommended to use a multimeter for testing. It is also possible to use a multimeter when there are no other measuring tools available.
Operation method:
Rotate the multimeter to the AC voltage range, conduct live measurement, and measure the metal casing of the equipment suspected of leakage.
When measuring, one probe is connected to the casing and the other probe is grounded. If the displayed voltage is higher than 30V, test again. If the power supply is confirmed to be higher than 30V, it indicates leakage. If it is lower than 30V, it is generally normal. You can also adjust the pen heads of the zero and live wire meters and measure them once to determine.
summary
Use a multimeter to test for short circuits, open circuits, AC voltage, DC voltage, resistance, current, etc.
Note: The red pen is positive and the black pen is negative. When measuring, the measurement category and range must be checked first. When the range cannot be estimated, select a larger range first, and then gradually change to a smaller range according to the value.
